U.S. patent application number 09/739682 was filed with the patent office on 2002-01-31 for image processing method and apparatus.
Invention is credited to Nakamura, Hiroaki.
Application Number | 20020012126 09/739682 |
Document ID | / |
Family ID | 18471410 |
Filed Date | 2002-01-31 |
United States Patent
Application |
20020012126 |
Kind Code |
A1 |
Nakamura, Hiroaki |
January 31, 2002 |
Image processing method and apparatus
Abstract
The image processing method and apparatus set preliminarily a
plurality of basic compression characteristics or basic expansion
characteristics of image information, select one or more basic
compression characteristics or basic expansion characteristics from
the plurality of basic compression characteristics or basic
expansion characteristics, and compress or expand gradation of the
image information using the one or more basic compression
characteristics or basic expansion characteristics. Optionally,
these method and apparatus analyze the image information, set a
processing condition for compressing or expanding the gradation of
the image information in accordance with an analysis result and
process the image information in accordance with the processing
condition. The method and apparatus can perform the dodging
processing having the excellent characteristics in a shorter period
of processing time than the conventional method and can favorably
enhance productivity of print production.
Inventors: |
Nakamura, Hiroaki;
(Kanagawa, JP) |
Correspondence
Address: |
SUGHRUE, MION, ZINN, MACPEAK & SEAS
2100 Pennsylvania Avenue, N.W.
Washington
DC
20037
US
|
Family ID: |
18471410 |
Appl. No.: |
09/739682 |
Filed: |
December 20, 2000 |
Current U.S.
Class: |
358/1.9 ;
358/302; 358/527 |
Current CPC
Class: |
H04N 1/6027 20130101;
H04N 1/4072 20130101 |
Class at
Publication: |
358/1.9 ;
358/527; 358/302 |
International
Class: |
G06K 015/02; H04N
001/407 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 20, 1999 |
JP |
11-360906 |
Claims
What is claimed is:
1. An image processing method comprising the steps of:
preliminarily setting a plurality of basic compression
characteristics or basic expansion characteristics of image
information; selecting one or more basic compression
characteristics or basic expansion characteristics from said
plurality of basic compression characteristics or basic expansion
characteristics; and compressing or expanding gradation of said
image information using the thus selected one or more basic
compression characteristics or basic expansion characteristics.
2. The image processing method according to claim 1, wherein said
plurality of basic compression characteristics or basic expansion
characteristics are preliminarily set in accordance with at least
one of an original type, an original size and an analysis result of
said image information.
3. The image processing method according to claim 1, wherein said
one or more basic compression characteristics or a plurality of
basic expansion characteristics are selected in accordance with at
least one of an original type, an original size and an analysis
result of said image information.
4. The image processing method according to claim 2, wherein said
original type is at least one of a negative film, a reversal film
and a black-and-white film, and wherein said original size is at
least one of a 135 size, a 240 size and a 120/220 size.
5. The image processing method according to claim 1, wherein said
one or more basic compression characteristics or basic expansion
characteristics are selected by a manual operation.
6. The image processing method according to claim 1, wherein said
basic compression characteristics or basic expansion
characteristics are provided as a parameter or a look-up table.
7. The image processing method according to claim 1, further
comprising the step of analyzing said image information, wherein
the step of compressing or expanding gradation of said image
information using said selected one or more basic compression
characteristics or basic expansion characteristics comprises the
steps of: setting a processing condition for compressing or
expanding the gradation of said image information using said
selected one or more basic compression characteristics or basic
expansion characteristics in accordance with said analysis result;
and processing said image information in accordance with the thus
set processing condition.
8. The image processing method according to claim 1, wherein the
step of compressing or expanding the gradation of said image
information using said selected one or more basic compression
characteristics or basic expansion characteristics comprises the
steps of: setting a processing condition for compressing or
expanding the gradation of said image information using said
selected one or more basic compression characteristics or basic
expansion characteristics by a manual operation; and processing
said image information in accordance with the thus set processing
condition.
9. The image processing method according to claim 7, wherein said
processing condition is set as a look-up table.
10. An image processing method comprising the steps of:
preliminarily setting a plurality of basic compression
characteristics or a plurality of basic expansion characteristics;
selecting one or more basic compression characteristics or one or
more basic expansion characteristics from said plurality of basic
compression characteristics or said plurality of basic expansion
characteristics; analyzing image information; setting a processing
condition for compressing or expanding gradation of said image
information using the thus selected one or more basic compression
characteristics or the thus selected one or more basic expansion
characteristics in accordance with an analysis result obtained by
thus analyzing the image information; and processing said image
information in accordance with the thus set processing
condition.
11. An image processing method comprising the steps of:
preliminarily setting a plurality of basic compression
characteristics or a plurality of basic expansion characteristics;
selecting one or more basic compression characteristics or one or
more basic expansion characteristics from said plurality of basic
compression characteristics or said plurality of basic expansion
characteristics; setting a processing condition for compressing or
expanding gradation of image information using the thus selected
one or more basic compression characteristics or the thus selected
one or more basic expansion characteristics by an manual operation;
and processing said image information in accordance with the thus
set processing condition.
12. An image processing apparatus comprising: a selecting device
for selecting one or more basic compression characteristics or
basic expansion characteristics from preliminarily set plurality of
basic compression characteristics or basic expansion
characteristics for use in compressing or expanding gradation of
image information supplied by an image information supply source;
and an image processing device for compressing or expanding the
gradation of said image information using said one or more basic
compression characteristics or basic expansion characteristics
selected by said selecting device.
13. The image processing apparatus according to claim 12, further
comprising: a setting section for analyzing the image information
and setting a processing condition for compressing or expanding the
gradation of said image information using said one or more basic
compression characteristics or basic expansion characteristics
selected by said selecting device in accordance with an analyzing
result obtained by thus analyzing the image information, wherein
said image processing device processes said image information in
accordance with the processing condition set by said setting
section.
14. The image processing apparatus according to claim 12, further
comprising: a setting section for setting a processing condition
for compressing or expanding the gradation of said image
information by a manual operation using said one or more basic
compression characteristics or basic expansion characteristics
selected by said selecting device, wherein said image processing
device processes said image information in accordance with the
processing condition set by said setting section.
15. The image processing apparatus according to claim 12, wherein
said selecting device selects said one or more basic compression
characteristic or basic expansion characteristics in accordance
with at least one of an original type of an image as an image
information source, an original size of the image as the image
information source and an analysis result of said image
information.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to the field of digital image
processing technology applied to digital photoprinters and the
like. More specifically, the present invention relates to an image
processing method and apparatus which can promptly perform image
processing capable of reproducing a high-quality image without a
washed-out highlight in a bright portion or a flat (dull) shadow in
a dark portion even in a scene in which a subject is taken with
backlight or an electronic flash.
[0002] Heretofore, the images recorded on photographic films such
as negatives and reversals (which are hereunder referred to simply
as "films") have been commonly printed on light-sensitive materials
(photographic paper) by means of so-called direct (analog) exposure
in which the film image is projected onto the light-sensitive
material to expose it.
[0003] A new technology has recently been introduced and this is a
printer that relies upon digital exposure. Briefly, the image
recorded on a film is read photoelectrically, converted to digital
signals and subjected to various image processing operations to
produce image data for recording purposes; recording light that has
been modulated in accordance with the image data is used to scan
and expose a light-sensitive material to record a latent image,
which is subsequently developed to produce a (finished) print. The
printer operating on this principle has been commercialized as a
digital photoprinter.
[0004] The digital photoprinter basically comprises a scanner
(image reading apparatus) for reading an image recorded on the film
photoelectrically by projecting a reading light to a film and
reading its projection light, an image processing apparatus for
carrying out a predetermined image processing on an input image
data read by the scanner or another image data supplied by a
digital camera or the like so as to obtain an image data for image
recording, that is, an exposure condition, a printer (image
recording apparatus) for recording the image as a latent image by
exposing a light-sensitive material by, for example, scanning with
light beam corresponding to the output image data outputted from
the image processing apparatus, and a processor (developing
apparatus) for carrying out development processing on the
light-sensitive material exposed by the printer so as to produce a
finished print in which the image is reproduced.
[0005] In the digital photoprinter having such features, images are
handled as digital image data so that image processing (image
adjustment) can be performed by image data processing. Therefore,
gradation adjustment, color balance adjustment, color/density
adjustment, sharpness processing and the like are favorably
performed to produce a high-quality print which has never been
realized by a conventional direct exposure. Moreover, in the
digital photoprinter, an image taken by the digital camera or the
like can be outputted as a print.
[0006] As an embodiment of the above-described image processing,
included is a case that a dodging effect on a print by direct
exposure can also be imparted by processing image data.
[0007] Shooting conditions of a photograph are not fixed and there
are many cases that a difference between brightness and darkness of
an image, namely, a range from the minimum density to the maximum
density of the image recorded on the film (difference between
minimum and maximum densities equals dynamic range of image
density), is very large, as is found in a scene in which the
subject is taken with backlight or the electronic flash.
[0008] However, a reproducible density range of the light-sensitive
material (photographic paper) is narrower than that of the film.
Therefore, if a print is produced by exposing (printing) the
light-sensitive material with a conventional method using a film
image having a wide dynamic range, the image is not appropriately
reproduced in some cases. For example, when the print is produced
using the film image in which a person is taken with backlight, if
exposure is executed such that the person comes out to be a
favorable image, a bright portion such as sky will become the
washed-out highlight. On the other hand, if exposure is executed
such that the sky comes out to be a favorable image, the person
will become the flat (dull) shadow.
[0009] To cope with the problem, in a conventional printer using an
areal exposure, when the print is produced from the film image
having such a wide dynamic range, there has heretofore been
employed a so-called dodging technique.
[0010] The dodging technique is a method of obtaining a print in
which an entire density range of the image recorded on the film is
appropriately reproduced in such a manner that, for example, if the
print is produced from a negative film, an amount of exposure light
is increased to a bright portion in which the image tends to become
the washed-out highlight and, on the other hand, an amount of
exposure light is reduced to a dark portion in which the image
tends to become the flat (dull) shadow employing a method of
inserting a light-shading plate, an ND (neutral density) filter or
the like in an optical path of the exposure light and so forth.
[0011] The present applicant has proposed an image processing
method in which reproduction of an image imparted with a similar
effect in the digital photoprinter or the like to a dodging effect
in direct exposure became possible by processing image data and an
image processing apparatus using the above-described method (see
Unexamined Published Japanese Patent Application (kokai)
No.10-13680).
[0012] The image processing of interest (hereinafter referred to
conveniently as "dodging processing") performs analysis of the
image (image data) supplied by the scanner or the like and, in
accordance with an analysis result, compresses (or expands)
gradation of the image such that an entire density range recorded
on the film is appropriately reproduced whereby dynamic range of
the image is compressed (or expanded) so as to be within a range
corresponding to an output apparatus.
[0013] Specifically, a bright portion (low density portion) and a
dark portion (high density portion) are compressed independently in
a linear or non-linear manner without changing an intermediate
density portion of the image in accordance with the analysis result
of the image.
[0014] For example, in a system in which image data of the bright
portion (high density portion of the negative film: low density
portion of a reproduced image) in the photographed scene has a
large value, the gradation is compressed by decreasing the image
data in the bright portion (image data being large) in which the
image tends to be the washed-out highlight and increasing the image
data in the dark portion in which the image tends to be the flat
(dull) shadow.
[0015] Therefore, according to the above-described dodging
processing, the image having an extremely wide density range
recorded on the film can appropriately be reproduced on the
light-sensitive material so that, even if the image has a wide
dynamic range as found in a scene in which the subject is taken
with backlight or the electronic flash, the print reproducing the
high-quality image in which a primary subject such a person's face
or the like is appropriately reproduced by means of substantially
reducing the washed-out highlight in the bright portion or the flat
(dull) shadow in the dark portion can be outputted.
SUMMARY OF THE INVENTION
[0016] An object, therefore, of the present invention is to provide
an image processing method and apparatus which can perform the
dodging processing having the above-described excellent
characteristics in a shorter period of processing time than the
conventional method and can favorably enhance productivity of print
production, for example, by being utilized in the above-described
digital photoprinter.
[0017] In order to attain the object described above, the present
invention provides an image processing method comprising the steps
of: preliminarily setting a plurality of basic compression
characteristics or basic expansion characteristics of image
information; selecting one or more basic compression
characteristics or basic expansion characteristics from the
plurality of basic compression characteristics or basic expansion
characteristics; and compressing or expanding gradation of the
image information using the thus selected one or more basic
compression characteristics or basic expansion characteristics.
[0018] Preferably, the plurality of basic compression
characteristics or basic expansion characteristics are
preliminarily set in accordance with at least one of an original
type, an original size and an analysis result of the image
information.
[0019] Preferably, the one or more basic compression
characteristics or a plurality of basic expansion characteristics
are selected in accordance with at least one of an original type,
an original size and an analysis result of the image
information.
[0020] Preferably, the original type is at least one of a negative
film, a reversal film and a black-and-white film, and wherein the
original size is at least one of a 135 size, a 240 size and a
120/220 size.
[0021] Preferably, the one or more basic compression
characteristics or basic expansion characteristics are selected by
a manual operation.
[0022] Preferably, the basic compression characteristics or basic
expansion characteristics are provided as a parameter or a look-up
table.
[0023] It is preferable that the image processing method further
comprises the step of analyzing the image information, wherein the
step of compressing or expanding gradation of the image information
using the selected one or more basic compression characteristics or
basic expansion characteristics comprises the steps of: setting a
processing condition for compressing or expanding the gradation of
the image information using the selected one or more basic
compression characteristics or basic expansion characteristics in
accordance with the analysis result; and processing the image
information in accordance with the thus set processing
condition.
[0024] Preferably, the step of compressing or expanding the
gradation of the image information using the selected one or more
basic compression characteristics or basic expansion
characteristics comprises the steps of: setting a processing
condition for compressing or expanding the gradation of the image
information using the selected one or more basic compression
characteristics or basic expansion characteristics by a manual
operation; and processing the image information in accordance with
the thus set processing condition.
[0025] Preferably, the processing condition is set as a look-up
table.
[0026] The present invention provides an image processing method
comprising the steps of: preliminarily setting a plurality of basic
compression characteristics or a plurality of basic expansion
characteristics; selecting one or more basic compression
characteristics or one or more basic expansion characteristics from
the plurality of basic compression characteristics or the plurality
of basic expansion characteristics; analyzing image information;
setting a processing condition for compressing or expanding
gradation of the image information using the thus selected one or
more basic compression characteristics or the thus selected one or
more basic expansion characteristics in accordance with an analysis
result obtained by thus analyzing the image information; and
processing the image information in accordance with the thus set
processing condition.
[0027] The present invention provides an image processing method
comprising the steps of: preliminarily setting a plurality of basic
compression characteristics or a plurality of basic expansion
characteristics; selecting one or more basic compression
characteristics or one or more basic expansion characteristics from
the plurality of basic compression characteristics or the plurality
of basic expansion characteristics; setting a processing condition
for compressing or expanding gradation of image information using
the thus selected one or more basic compression characteristics or
the thus selected one or more basic expansion characteristics by an
manual operation; and processing the image information in
accordance with the thus set processing condition.
[0028] In order to attain the object described above, the present
invention provides an image processing apparatus comprising: a
selecting device for selecting one or more basic compression
characteristics or basic expansion characteristics from
preliminarily set plurality of basic compression characteristics or
basic expansion characteristics for use in compressing or expanding
gradation of image information supplied by an image information
supply source; and an image processing device for compressing or
expanding the gradation of the image information using the one or
more basic compression characteristics or basic expansion
characteristics selected by the selecting device.
[0029] It is preferable that the image processing apparatus further
comprises: a setting section for analyzing the image information
and setting a processing condition for compressing or expanding the
gradation of the image information using the one or more basic
compression characteristics or basic expansion characteristics
selected by the selecting device in accordance with an analyzing
result obtained by thus analyzing the image information, wherein
the image processing device processes the image information in
accordance with the processing condition set by the setting
section.
[0030] It is also preferable that the image processing apparatus
further comprises: a setting section for setting a processing
condition for compressing or expanding the gradation of the image
information by a manual operation using the one or more basic
compression characteristics or basic expansion characteristics
selected by the selecting device, wherein the image processing
device processes the image information in accordance with the
processing condition set by the setting section.
[0031] Preferably, the selecting device selects the one or more
basic compression characteristic or basic expansion characteristics
in accordance with at least one of an original type of an image as
an image information source, an original size of the image as the
image information source and an analysis result of the image
information.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is a block diagram showing an embodiment of a digital
photoprinter utilizing an image processing method and apparatus of
the present invention;
[0033] FIG. 2 is a block diagram showing an embodiment of the image
processing apparatus of the digital photoprinter shown in FIG.
1;
[0034] FIG. 3 is a block diagram showing an embodiment of an image
processing subsection of the image processing apparatus shown in
FIG. 2;
[0035] FIG. 4 shows an example of an image density histogram;
[0036] FIGS. 5A, 5B and 5C are each an illustration showing an
example of a basic compression LUT;
[0037] FIGS. 6A, 6B, 6C and 6D are each an illustration showing
another example of a basic compression LUT;
[0038] FIGS. 7A and 7B are each an illustration showing an example
of an LUT for determining a coefficient multiplied to a basic
compression LUT;
[0039] FIGS. 8A and 8B are each an illustration showing another
example of an LUT for determining a coefficient multiplied to a
basic compression LUT;
[0040] FIG. 9 shows an example of cumulative histogram of
density;
[0041] FIGS. 10A, 10B and 10C are each an example of a basic
expansion LUT; and
[0042] FIG. 11 is an illustration showing an example of an LUT for
determining a coefficient multiplied to a basic expansion LUT.
DETAILED DESCRIPTION OF THE INVENTION
[0043] Hereinafter, an image processing method and apparatus
according to the present invention will now be described in detail
with reference to the preferred embodiments shown in the
accompanying drawings.
[0044] FIG. 1 is a block diagram showing an embodiment of a digital
photoprinter utilizing an image processing method and apparatus
according to the present invention.
[0045] The digital photoprinter (hereinafter referred to simply as
"photoprinter") 10 shown in FIG. 1 basically comprises a scanner
(image reading apparatus) 12, an image processing apparatus 14 and
a printer 16. Connected to the image processing apparatus 14 are a
manipulating unit 18 having a keyboard 18a and a mouse 18b for
inputting or setting various conditions, selecting and commanding a
specific processing step and entering a command and so forth for
effecting color/density correction, as well as a display 20 for
representing a simulation image for verification, various
manipulative commands and the like.
[0046] The scanner 12 is an apparatus with which the images
recorded on the film F are read photoelectrically frame by frame.
It comprises a white light source 22, a variable diaphragm 24, a
color filter plate 26, a diffuser box 28 which diffuses the reading
light incident on the film F so that it becomes uniform across the
plane of the film F, an imaging lens unit 32, an image sensor 34
which is an area CCD sensor, an amplifier (Amp) 36 and an A/D
(analog/digital) converter 38.
[0047] In the photoprinter 10, dedicated carriers are available
that can be loaded into the body of the scanner 12 in accordance
with the type or the size of the film used (e.g. whether it is a
film of the Advanced Photo System (APS) or a negative or reversal
film of 135 or 120/220 size), the format of the film (e.g. whether
it is a film or a slide) or other factor. By replacing one carrier
with another, the photoprinter 10 can be adapted to process various
kinds of films in various modes. Therefore, the size of the film F
(size of an original) which is subjected to reading processing
(print production) can be detected by the carrier loaded to the
body of the scanner 12.
[0048] The images (frames) that are recorded on the film and which
are subjected to the necessary procedure for print production are
transported to and held in a specified reading position by means of
the above-described carriers.
[0049] The film F is photoelectrically provided with records of
various bar codes such as a DX code, an expanded DX code, an FNS
code and the like representing film type and other kinds of
information. Moreover, the APS film has a magnetic recording medium
formed thereon in which various types of film information such as
an ID number, a film type and the like, various types of
picture-taking information such as presence or absence of light
emission from the electronic flash when taking a picture, date and
time of taking the picture and the like are recorded. Therefore, a
type of an original can be known from information which the DX code
and the magnetic recording medium have.
[0050] The respective information as described above are read by
the carrier at the time of image reading of the film F and sent to
the image processing apparatus 14.
[0051] When such a scanner 12 reads the image recorded on the film
F, reading light issued from the light source 22 has its quantity
adjusted by the variable diaphragm 24 passes through the color
filter plate 26 to be adjusted in color and is diffused by passing
through the diffuser box 28. The reading light is then incident on
the film F held in a predetermined reading position by the carrier
and passes therethrough to produce projection light carrying the
image recorded on the film F.
[0052] The resultant projection light is focused on a
light-receiving plane of the image sensor 34 by the focusing lens
unit 32 whereupon the image recorded on the film F is read
photoelectrically.
[0053] An output signal of the image sensor 34 is amplified by the
amplifier 36, converted to digital signal by the A/D converter 38
and sent to the image processing apparatus 14.
[0054] The color filter plate 26 is a turret having a color filter
corresponding to each of R (red), G(green) and B(blue) which is
rotated by a rotating device (not shown) to insert each color
filter in the optical path of the reading light.
[0055] In the illustrated scanner 12, the image recorded on the
film F is captured by separating it into three primary colors R, G
and B as respective color filters of the color filter plate 26 are
sequentially inserted therein and reading the thus separated images
into three primary colors one at a time, namely, three times
altogether.
[0056] In the scanner 12, the image recorded on the film F is
captured by two scans, the first being prescan at low resolution
and the second being fine scan for obtaining image data
corresponding to print output.
[0057] On this occasion, the prescan is performed at a
preliminarily set prescan reading condition which ensures that the
images on all films which the scanner 12 is about to read can be
read without saturating the image sensor 34. On the other hand, the
fine scan is performed at a fine scan reading condition for each
frame, which is set based on the prescanned data so that the image
sensor 34 is saturated by a density slightly lower than the minimum
density of the image (frame) of interest.
[0058] The output signals for prescan and fine scan are essentially
of the same data with each other except for resolution and output
levels.
[0059] It should be noted that an image data supply source which
supplies image data to the image processing apparatus according to
the present invention is not limited to such a scanner 12.
[0060] For example, the illustrated scanner 12 has separated the
image into three primary colors using the white light source and
the color filter plate; however, the scanner which reads the image
by separating it into three primary colors using the light source
provided with an LED or the like that individually emits a reading
light corresponding to each of three primary colors may be
permissible. As another aspect, the scanner which reads the image
recorded on the film by slit scanning using CCD line sensors for
respective three colors instead of the area CCD sensor may also be
permissible.
[0061] Moreover, image processing may be performed by receiving
image data not only from the scanner which photoelectrically reads
the image recorded on the film but also from various image data
supply sources which include, for example, an image reading
apparatus for reading the image on a reflection material, an image
pickup device such as a digital camera or the like, a communication
device such as a computer communication network or the like and a
recording medium such as a floppy disk or the like.
[0062] As described above, the output signal (image data) from the
scanner 12 is outputted to the image processing apparatus 14.
[0063] FIG. 2 shows a block diagram of the image processing
apparatus 14. The image processing apparatus (hereinafter referred
to simply as "processing apparatus") 14, as shown in FIG. 2,
comprises a data processing section 46, a log converter 48, a
prescan (frame) memory 50, a fine scan (frame) memory 52, a
condition setting section 54, a prescan processing section 56 and a
fine scan processing section 58.
[0064] FIG. 2 mainly shows sites relating to the image processing.
However, the processing apparatus 14 also controls and manages
overall operation of the photoprinter 10 and, in addition to the
sites shown in FIG. 2, the processing apparatus 14 includes a CPU
for controlling the overall operation, a memory or the like for
storing information necessary for operation or the like of the
photoprinter 10. The manipulating unit 18 and the display 20 are
connected to respective sites via this CPU (CPU bus) and the
like.
[0065] Respective output signals for red, green and blue outputted
from the scanner 12 are subjected to predetermined processing for
DC offset correction, darkness correction, shading correction and
the like by the data processing section 46 and then logarithmically
converted to digital image (density) data (by such as an LUT
(look-up table) or the like) in the log converter 48. Prescanned
(image) data is stored in the prescan memory 50 and fine scanned
(image) data is stored in the fine scan memory 52.
[0066] The condition setting section 54 for setting an image
processing condition of each image (frame) in the prescan
processing section 56 (its image processing subsection 68) and the
fine scan processing section 58 (its image processing subsection
72) comprises a setup subsection 62, a key adjusting subsection 64
and a parameter coordinating subsection 66.
[0067] The setup subsection 62 is a site in which the image
processing condition for each frame is set by performing an image
analysis using the prescanned data (automatic setup operation
processing).
[0068] Specifically, based on the prescanned data, the setup
subsection 62 constructs an image density histogram, calculates
image characteristic quantities such as an LATD (large area
transmission density), specified % points of frequencies of the
image density histogram such as maximum and minimum densities and
the like, an average density and the like and then, in accordance
with the density histogram or the image characteristic quantities,
calculates a reading condition for the fine scan and image
processing conditions such as various types of LUTs, matrix
operational formulas or the like in the image processing
subsections 68 and 72 by a known method such as a matrix operation,
an image processing algorithm or the like.
[0069] Moreover, the setup subsection 62 has a selecting part 62a
that comprises a memory therein in which a plurality of preset
basic compression characteristics and a plurality of preset basic
expansion characteristics are stored. The selecting part 62a
selects one or more basic compression (expansion) characteristics
from the plurality of basic compression characteristics and the
plurality of basic expansion characteristics thus stored in the
built-in memory in accordance with at least one of the type of the
original, the size of the original and an result of the image
analysis (automatic setup operation). The setup subsection 62 sets
a dodging processing condition using the basic compression
(expansion) characteristics selected by the selecting part 62a.
Namely, the setup subsection 62 is a major portion composing the
image processing apparatus executing the image processing method
according to the present invention.
[0070] This point will be discussed later in detail.
[0071] The key adjusting subsection 64 calculates an adjusting
quantity for the image in accordance with various instructions for
adjustment inputted by various adjusting keys set on the keyboard
18a such as a density adjusting key, an adjusting key for each
color of C (cyan), M (magenta) and Y (yellow), a gradation
(.gamma.: gamma) adjusting key, a bright portion adjusting key, a
dark portion adjusting key, a sharpness adjusting key, a saturation
adjusting key and the like, and the mouse 18b and then supplies the
thus calculated adjusting quantity to the parameter coordinating
subsection 66.
[0072] The parameter coordinating subsection 66 receives the image
processing condition set by the setup subsection 62 and sets the
thus received image processing condition at the image processing
subsection 68 in the prescan processing section 56 and the image
processing subsection 72 in the fine scan processing section 58.
The parameter coordinating subsection 66 further performs an
adjustment (correction) of the image processing condition set in
each of the processing section in accordance with the adjusting
quantity of the image calculated by the key adjusting subsection
64, creation of a correction condition with which such adjustment
(correction) is carried out and setting of the thus created
correction condition in each of the processing section.
[0073] In the illustrated processing apparatus, the prescanned data
stored in the prescan memory 50 and the fine scanned data stored in
the fine scan memory 52 are basically processed in the prescan
processing section 56 and in the fine scan processing section 58,
respectively.
[0074] The prescan processing section 56 comprises the image
processing subsection 68 and a data converting subsection 70. On
the other hand, the fine scan processing section 58 comprises the
image processing subsection 72 and a data converting subsection
74.
[0075] The image processing subsection 68 of the prescan processing
section 56 and the image processing subsection 72 of the fine scan
processing section 58 have basically the same construction except
that the pixel densities of image data to be processed are
different from each other and carry out the same processing.
[0076] Therefore, the image processing subsection 72 of the fine
scan processing section 58 is explained below as a representative
example.
[0077] The image processing section 72 (68) comprises a first LUT
76, a first matrix calculator (hereinafter referred to simply as
"MTX") 78 and a dodging processing block 80.
[0078] As described above, the image processing condition in each
of the above-described processing sites is set in the condition
setting section 54.
[0079] The first LUT 76 reads out the image data stored in the fine
scan memory 52 (prescan memory 50) and performs the gray balance
(color balance) correction, density correction and gradation
correction. It is composed of LUTs which are connected to each
other in a cascade fashion to perform respective corrections.
[0080] The first MTX 78 performs color correction of the image
(image data) processed by the first LUT 76. That is, the first MTX
78 performs a matrix calculation set in accordance with a spectral
characteristic of the film F, a spectral characteristic of the
light-sensitive material (photographic paper), a characteristic of
development processing and the like so that the image to be
outputted as a print is finished in an appropriate color.
[0081] The dodging processing block 80 is a site which performs
digital dodging processing (imparts a digital dodging effect
similar to that of a print produced by direct exposure by means of
image data processing); it comprises a second MTX 82, a low-pass
filter (LPF) 84, a second LUT 86 and an adder 88.
[0082] When the dodging processing is performed, the image data
processed by the first MTX 78 is supplied to the second MTX 82 and
the adder 88. On the other hand, when the dodging processing is not
performed, the first MTX 78 and the data converting subsection 74
(70) are directly connected to each other via a bypass and the
image data is supplied from the first MTX 78 to the data converting
subsection 74.
[0083] The second MTX 82 receives the image data of R, G and B
images sent from the first MTX 78 to create the image data
(luminance image data) of luminance images of the images of
interest.
[0084] A method of creating the luminance image data is not limited
to a particular way, but a method of using a value of one-third of
the mean value of each of the RGB image data, a method of
converting color image data into the luminance image data using a
YIQ base and the like are exemplified. For example, a method of
creating the luminance image data by calculating only a Y component
of the YIQ base from the red, green and blue image data by a
formula, Y=0.3R+0.59G+0.11B, is exemplified.
[0085] The LPF 84 two-dimensionally shades off the luminance image
by processing the luminance image data created by the second MTX 82
and taking out a low frequency component therefrom thereby
obtaining an unsharp image data of a read-out image.
[0086] The LPF 84 is used for compressing the image gradation and,
when the image gradation is expanded to the contrary, the second
MTX 82 and the second LUT 86 are connected to each other via a
bypass whereby the luminance image data created by the second MTX
is sent to the second LUT.
[0087] As the LPF 84, a finite impulse response (FIR) type low-pass
filter which is ordinarily used for creating an unsharp image may
be used; however, preferably, an infinite impulse response (IIR)
type low-pass filter is used because it can create unsharp image
data in which the image is made unsharp to a great extent in a
small circuit.
[0088] Since the prescanned image data and the fine scanned image
data are different from each other in resolution of the images, if
they are processed by the same low-pass filter, the images to be
reproduced by the display 20 and the printer 16 will be different
from each other. Accordingly, it is necessary to change a frequency
characteristic of the LPF 84 in accordance with the resolution each
of the prescanned data and the fine scanned data.
[0089] Specifically, an amount of shading-off of the unsharp image
data used for representation on the display 20 may be reduced by a
ratio of resolution. Namely, when the ratio of resolution is
represented by m; the cut-off frequency of the prescanned data is
represented by fc(p); the cut-off frequency of the fine scanned
data is represented by fc(f), the low-pass filter may be designed
to satisfy the following formula:
fc(p).apprxeq.mfc(f)
[0090] The unsharp image data created by the LPF 84 (or the
luminance image data created by the second MTX) is processed by a
gradation compressing (expanding) LUT in the second LUT 86.
[0091] As described above, the image density range which can be
recorded on the film F is ordinarily wider than the reproducible
image density range in the print and, for example, in the scene in
which the subject is taken with backlight or the electronic flash,
the image having the density range which greatly exceeds the
reproducible area in the print may be recorded in some cases.
[0092] FIG. 4 shows an example of an image density histogram (film
density) created from the image data of a read-out negative film by
the setup subsection 62.
[0093] When the reproducible area in the print is located within
the region of image density shown by broken lines in FIG. 4, all
the pixels of the images shown by a to c can not be reproduced in
the print. That is, a high image density portion outside of the
reproducible area (where the intensity of read-out signals is weak:
where the image data is large), namely, the bright portion in the
print (recorded scene) will become the washed-out highlight, while
a low image density portion outside of the reproducible area,
namely, the dark portion in the print will become the flat (dull)
shadow. To obtain the image in which all the image data is
reproduced, a range from the maximum density to the minimum density
of the image (dynamic range of the image density) must be
compressed so that it corresponds to the reproducible area in the
print. That is, it is necessary to process the image data in such a
manner that the dynamic range is compressed by compressing the
gradation of the image (image data) so as to allow it to correspond
to the reproducible area in the print whereupon an effect similar
to that obtained by the dodging technique using ordinary direct
exposure is achieved.
[0094] When the image of the film F serving as the original is over
exposed, there is a tendency that the image comes to have high
density as a whole thereby producing the image the bright portion
of which is dull in the print. On the other hand, when the image is
under-exposed, there is a tendency that the image comes to have low
density as a whole thereby producing the image the dark portion of
which is dull in the print.
[0095] Therefore, in order to obtain a high-quality image on this
occasion, it is necessary to enhance the contrast by increasing an
inclination of a gradation curve. Specifically, when the image is
over-exposed, it is necessary to increase the inclination of the
gradation curve in the high density portion (bright portion in the
print) within the reproducible area in the print; when the image is
under-exposed, it is necessary to increase the inclination of
gradation curve in the low density portion (dark portion in the
print) within the reproducible area in the print. In other words,
when the under-/over-exposed image is corrected, it is necessary to
expand the gradation to the contrary.
[0096] In the illustration shown in FIG. 4, the image data comes to
correspond to a density reproducible area in the print by
non-linearly compressing or expanding the gradation of primary
image data by means of adding the above-described unsharp image
data (luminance image data) processed by the gradation compression
(expansion) LUT of the second LUT 86 to the primary image data
processed by the first MTX 78. In this way, the gradation, the
density or the dynamic range of the bright/dark portion of the
image data to be outputted is appropriately set whereby, even in
the scene in which the subject is taken with backlight, the
electronic flash or the like, an appropriate print having a
high-quality image therein can be outputted consistently.
[0097] Namely, the gradation compression (expansion) LUT of the
second LUT 86 is an LUT for processing the above-described unsharp
image data (luminance image data) to obtain image data to be used
for processing the primary image data such that the gradation
thereof or the like is appropriately set.
[0098] As an example, the selecting part 62a of the setup
subsection 62 stores three basic compression LUTs, as shown in
FIGS. 5A to 5C, which show basic compression characteristics. Yc in
each of FIGS. 5A to 5C represents the center of each density, for
example, about 0.8 by the density D.
[0099] The basic compression LUT shown in FIG. 5A denotes
compression characteristics which put emphasis on appropriate
reproduction of the bright and dark portions. Namely, both the
washed-out highlight in the bright portion and the flat (dull)
shadow in the dark portion are decreased by compressing the
gradation by means of intensively compressing the density range
which greatly exceeds the reproducible area in the print without
compressing the intermediate gradation whereby density ranges in
both portions can favorably be reproduced.
[0100] The basic compression LUT shown in FIG. 5B denotes
compression characteristics which compress the entire area from the
bright portion to the dark portion. According to this basic
compression LUT, the gradation is compressed such that the entire
area thereof comes close to be of an intermediate gradation thereby
enhancing a ratio of appropriate images (acceptance). Namely, this
basic compression LUT enhances the ratio of prints which can be
outputted (verification OK) only by means of an automatic
correction by the processing apparatus 14 so that it serves as a
basic compression LUT for enhancing productivity in a lab shop and
the like.
[0101] The basic compression LUT shown in FIG. 5C denotes
compression characteristics which compress the range in the bright
portion that greatly exceeds the reproducible area in the print and
the entire range in the dark portion. Further, in place of the
above LUT or in addition to the above LUT, another basic
compression LUT which has compression characteristics adverse to
those of the LUT shown in 5C may be stored.
[0102] As an example, the selecting part 62a selects one or a
plurality of basic compression LUTs setting the type of the
original as a parameter, for example, in accordance with the type
of the film F, that is, a negative, reversal or black-and-white
film. Namely, in the above example, one or more basic compression
characteristics can be defined in accordance with each type of the
original. The type of the original may be obtained by the bar code
such as the DX code or the like, magnetic information of the
Advanced Photo System (APS) read by the carrier of the scanner or
an input by the operator.
[0103] In the above-described example, for example, if the film F
is the negative film, the selecting part 62a selects the basic
compression LUT shown in FIG. 5B and, if the film F is the reversal
film or the black-and-white film, it selects the basic compression
LUT shown in FIG. 5A.
[0104] Further, as a selection parameter for the basic compression
LUT, the size of the original such as 135, 240 or 120/220 size in
the case of the film F can favorably be utilized. Namely, in the
above-described example, one or more basic compression LUTs can be
defined in accordance with the size of the original. The size of
the original may be obtained by the bar-code such as the DX code or
the like or the magnetic information of the APS read by the carrier
loaded in the scanner or input by the operator.
[0105] In the above-described example, for example, if the film F
is of the 135 or 240 size, the selecting part 62a selects the basic
compression LUT shown in 5B and, if the film is of the 120/220
size, it selects the basic compression LUT shown in 5A.
[0106] As the selection parameter for the basic compression LUT,
the image analysis result or selection/setting by the operator is
also favorable.
[0107] When the result of image analysis is used, a ratio between
regions of the bright portion and dark portion, an image contrast
and the like can be used as an analysis result. For example, it is
possible that the image in which the region of the bright portion
is dominant is an image in a scene in which a subject is taken with
backlight; therefore, basic compression characteristics shown in
FIG. 5C are selected so that the gradation compression is performed
positively on the portion having a darker density than
intermediate. To the contrary, for the image having an extremely
large contrast, the basic compression characteristics shown in FIG.
5(B) are selected so that the gradation can be compressed in an
overall manner.
[0108] Namely, as a selection method of the basic compression LUT
based on the image analysis result, for example, when the image
density histogram information is used, if the ratio of the image
bright and dark portions is large and, moreover, if difference of
densities between the bright and dark portions is large, then the
basic compression LUT shown in 5A is selected; if the ratio of the
image bright portion is large and, moreover, if the density in the
bright portion is extremely large, then the basic compression LUT
shown in 5C is selected; and in the other cases than the
above-described cases, the basic compression LUT shown in 5B is
selected.
[0109] In this occasion, the analysis results of the image to be
used for selection of the basic compression LUT, for example, the
ratio, densities, difference of densities or the like of the image
bright and dark portions may appropriately be set in accordance
with apparatus characteristics of the photoprinter 10 or the
like.
[0110] The basic compression LUTs shown in FIGS. 5A to 5C
correspond to the compression of the dynamic range across the
entire density range from the bright portion to the black portion.
However, the present invention is not limited to the above example
but the selecting part 62a may independently have a plurality of
basic compression LUTs in each of the bright and dark portions and
select a basic compression LUT in each of the bright and dark
portions in accordance with a selection parameter such as the type
of the original, the size of the original or the like so that the
thus selected basic compression LUTs may be set as the basic
compression LUTs which correspond to the compression of the dynamic
range across the entire density range.
[0111] FIGS. 6A to 6D each shows an example of the above-described
aspect.
[0112] Among examples shown in FIGS. 6A to 6D, FIGS. 6A and 6C show
examples which correspond to compression in the bright portion;
FIGS. 6B and 6D show examples which correspond to compression in
the dark portion. The basic compression LUTs shown in FIGS. 6A to
6D are illustrations in which the basic compression LUTs shown in
FIGS. 5A and 5B have been divided into the bright and dark portion
sides by the point of Yc.
[0113] Setting, for example, at least one of the type of the
original, size of the original, the image analysis result and
selection/setting by the operator as a parameter and, in accordance
with the thus set parameter, the selecting part 62a of the setup
subsection 62 selects one or more basic compression LUTs shown in
FIGS. 6A and 6C which compress the bright portion and one or more
basic compression LUTs shown in 6B and 6D which compress the dark
portion and add the thus selected basic compression LUTs with each
other to produce a basic compression LUT which corresponds to the
entire density range.
[0114] It should be noted that, in the image processing apparatus
according to the present invention, the basic compression LUT to be
selected is not limited to one but a plurality of the basic
compression LUTs are permissible as described above. On this
occasion, for example, selected basic compression LUTs may be used
by synthesizing them with each other or connecting them to each
other in a cascade fashion.
[0115] Moreover, the parameter to be used for selecting the basic
compression LUT is not limited to one, but a plurality of
parameters may be used for selecting a basic characteristic
LUT.
[0116] Further, it should be noted that the selection method of the
basic compression LUT corresponding to the parameter is not limited
in any particular way, but the selecting part 62a may store it as a
predetermined file or otherwise the setup subsection 62 may
appropriately determine it in accordance with a selection
parameter.
[0117] The setup subsection 62 automatically sets up the dodging
processing condition in accordance with the image analysis using
the basic compression LUT thus selected by the selecting part 62a.
It should be noted that the setup subsection 62 may of course set
the basic compression LUT which the selecting part 62a thereof has
selected as a dodging processing condition without adding any
change thereto.
[0118] In the present invention, a plurality of the basic
compression LUTs or basic expansion LUTs (compression or expansion
characteristics) have previously been set by the above-described
method and then the basic compression LUT or the like is selected
in accordance with the type of the original, the size of the
original, the image analysis result, selection/setting by the
operator or the like thereby setting the compression (expansion)
LUT of the dodging processing (dodging processing condition) using
the thus selected basic compression LUT or the like. In doing this
way, even the scene in which the subject is taken with backlight or
the electronic flash can be subjected more promptly than in a
conventional way to dodging processing which substantially
decreases the washed-out highlight in the bright portion or the
flat (dull) shadow in the dark portion whereupon, for example,
productivity of prints in the photoprinter 10 can favorably be
enhanced.
[0119] Conveniently, when the Yc which is the intermediate density
is set as a border, the compression of the bright portion side is
set as g.sub.light and the compression of the dark portion side is
set as g.sub.dark, then the basic compression LUT is shown by the
following formula:
The basic compression LUT=g.sub.light+g.sub.dark
[0120] In the illustration, the compression ratio f.sub.auto
(gradation compression LUT which will be hereinafter referred to
simply as "compression LUT") of the dodging processing which is
automatically set up by the setup subsection 62 is determined by
the following formula using the selected basic compression LUT:
f.sub.auto=A.times.g.sub.light+B.times.g.sub.dark
[0121] In the above formula, coefficients A and B are set within
the ranges of 0.ltoreq.A.ltoreq.1, 0.ltoreq.B.ltoreq.1,
respectively, and they are appropriately determined in accordance
with image conditions, specifically, the image characteristics such
as the frequencies of both bright and dark portions, the maximum
and minimum image densities of the image density histogram, an
average image density or the like.
[0122] That is, in the case of the image of the histogram b shown
by the dot-dash-line in FIG. 4, since the dark portion (low density
on the film) has a high frequency, it can be determined that the
image is recorded using the electronic flash or the like at night.
In this type of the image, the compression ratio on the bright
portion side is set to have a large value, that is, the coefficient
A multiplied to g.sub.light is set to have a large value. When the
image is recorded using the electronic flash or the like at night,
since a primary subject such as a person or the like is ordinarily
located on the bright portion side of the histogram (a high density
side on the film), the image is likely to turn bright, washed-out
highlight. However, the above processing can make the primary
subject have an appropriate image density (brightness).
[0123] On the contrary, in the image of the histogram c shown by
the two-dot-and-dash-line in FIG. 4, since the bright portion has a
high frequency, it can be determined that the image of a snow scene
or a scene in which the subject is taken with backlight is
recorded. In this type of the image, the compression ratio on a
dark portion side is set to have a large value, that is, the
coefficient B multiplied to g.sub.dark is set to a large value. In
the scene in which the subject is taken with backlight or the like,
since a primary subject is ordinarily located on the dark portion
side of the histogram, the image is likely to turn dark. However,
the above processing can turn the primary subject to bright and
produce a high-quality image.
[0124] When the maximum and minimum densities of the image density
histogram are greatly dislocated from the print reproducible area,
the compression ratio must be increased at both the bright and dark
portions in order to appropriately reproduce all the images.
[0125] As a method of determining the coefficients A and B, there
is illustrated, for example, a method of preparing an LUT as shown
in FIG. 7A which shows the relationship between the image density
region a dislocated to the bright portion side and the coefficient
A and another LUT as shown in FIG. 7B which shows the relationship
between the image density region b dislocated to the dark portion
side and the coefficient B and determining the coefficients A and B
using the thus prepared LUTs. In the above method, a represents an
extent of an image density area which is dislocated from the print
reproducible area to the bright portion side; b represents an
extent of the image density area which is dislocated from the print
reproducible area to the dark portion side in the image density
histogram shown in FIG. 4 (both regions of a and b are illustrated
in the histogram a in FIG. 4).
[0126] Otherwise, there is also illustrated a method of determining
the coefficient A and the coefficient B. According to the method,
there are prepared an LUT showing the relationship between the
frequency on the dark portion side (cumulative percent=X%) and the
coefficient A as shown in FIG. 8A and another LUT showing the
relationship between the frequency on the bright portion side
(cumulative percent=Y%) and the coefficient B as shown in FIG. 8B.
Further, a cumulative histogram of the image density as shown in
FIG. 9 is prepared from the image density histogram and respective
cumulative percentages at the dark and bright portions are
calculated from a print reproduction limit P on the dark portion
side and a print reproduction limit Q on the bright portion side
using the thus prepared cumulative histogram thereby determining
the coefficients A and B using the LUTs shown in FIGS. 7A and
7B.
[0127] Other favorably exemplified methods than the above-described
methods include a method of determining the coefficients A and B by
first calculating coefficients A and B from each of the LUTs shown
in FIGS. 6A to 6D and FIGS. 7A and 7B and then averaging the thus
calculated respective coefficients As and coefficients Bs
separately and a method of determining the coefficients A and B by
first calculating coefficients As and Bs in the same way as in the
above-described method and then selecting coefficients A and B each
of which has a larger value than the other coefficients As and
Bs.
[0128] Furthermore, the coefficients A and B may be determined by
selecting which LUT to use on the basis of the histogram.
[0129] As described above, with respect to cases where the image
recorded on the film F is over-exposed or under-exposed, when the
film image is under-exposed, the inclination of the gradation curve
in the dark portion is increased, whereas when it is over-exposed,
the inclination of the gradation curve in the bright portion is
increased, to correct the above states. That is, when the image is
under-exposed or over-exposed, the setup subsection 62 sets the
gradation expansion LUT (hereinafter, referred to simply as
"expansion LUT") and expands the gradation of the image thereby
expanding the dynamic range on the contrary.
[0130] It should be noted that a method of discriminating between
the image is under-exposed and the image is over-exposed is not
particularly limited but any known method of discrimination based
on the image characteristic quantity, average image density,
maximum image density, minimum image density or the like obtained
from the image density histogram may be used.
[0131] In the selecting part 62a of the setup subsection 62, as an
example, basic expansion LUTs as shown in FIGS. 10A to 10C are
stored.
[0132] The selecting part 62a sets, for example, one or more of the
type of the original, the size of the original, the image analysis
result and the selection/setting by the operator as parameters and
selects at least one of the basic expansion LUTs shown in FIGS. 10A
to 10C in accordance with the thus set parameters.
[0133] As an example, in the case of over-exposure, the basic
expansion LUT shown in FIG. 10A is selected; in the case of
under-exposure, the basic expansion LUT shown in 10B is selected;
in the case of ultra-under-exposure or ultra-over-exposure, the
basic expansion LUT shown in 10C is selected.
[0134] Discrimination between the (ultra-) under-exposure and
(ultra-) over-exposure to be used when the basic expansion LUT is
selected may appropriately be set in accordance with the apparatus
characteristics of the photoprinter 10 or the like.
[0135] When the expansion of the bright portion for primarily
correcting the over-exposure is represented by q.sub.over and the
expansion of the dark portion for primarily correcting the
under-exposure is represented by q.sub.under, the basic expansion
LUT is shown, as in the same way as in the compression of the
above-described gradation, in the following formula:
The basic expansion LUT=q.sub.over+q.sub.under
[0136] Also, the expansion ratio q.sub.auto (expansion LUT) of the
dodging processing which the setup subsection 62 automatically sets
up is determined by the following formula by means of using the
selected basic expansion LUT:
q.sub.auto=A.times.q.sub.under+B.times.q.sub.over
[0137] In the above formula, the coefficients A and B are set
within the ranges of 0.ltoreq.A.ltoreq.1 and 0.ltoreq.B.ltoreq.1,
respectively, and they are appropriately determined in accordance
with the states of the image, specifically, the image
characteristic quantities such as the difference between the
minimum density of the image density histogram and the film base
density, frequencies of the bright and dark portions, the maximum
and minimum densities of the density histogram, the average density
and the like.
[0138] A method is illustrated in which a table showing the
coefficients A and B with respect to a difference between the
minimum density (D.sub.min) of the image density histogram and the
film base density is preliminarily created, for example, as shown
in FIG. 11, and then the coefficients A and B are determined using
the thus created table.
[0139] In the image processing apparatus according to the present
invention, the compression ratio or the expansion ratio by the
dodging processing is not limited to the type which the setup
subsection 62 automatically sets up but the compression LUT or the
expansion LUT may be created by adding an adjustment in accordance
with operator's manipulation of the keyboard (for example, the
above-described gradation adjustment key, bright portion adjustment
key or dark portion adjustment key) to the above-described
compression ratio f.sub.auto or expansion ratio q.sub.auto by the
operator. The adjustment of compression ratio or the expansion
ratio by the operator is described in commonly assigned Unexamined
Published Japanese Patent Application (kokai) No. 10-13680 in
detail.
[0140] It should be noted that the image processing apparatus
according to the present invention is not limited to the type which
performs both compression and expansion of the gradation but, for
example, the apparatus which stores a plurality of only basic
compression LUTs to perform only compression of the gradation is
permissible. Further, optionally (for example, when an image with
soft-focus finishing is required), expansion of the gradation may
be performed using the unsharp image data processed by the LPF
84.
[0141] The unsharp image data (luminance image data) processed by
the second LUT 86 as described above is supplied to the adder 88.
In the adder 88, the primary image data which has been processed by
the first MTX 78 and directly sent to the adder 88 and the unsharp
image data are added. By this operation, the gradation of the
primary image data is compressed (expanded) whereby a similar
effect as that obtained by carrying out the dodging technique using
areal exposure can be obtained.
[0142] In more detail, the unsharp image data which has been
processed by the compression LUT in the second LUT 86 becomes image
data which is negative value in the bright portion (image data is
larger) and positive (plus) value in the dark portion. Therefore,
the above-described unsharp image data is added to the primary
image data which has been processed by the first MTX 78 whereby the
primary image data in the bright portion comes to be small and that
in the dark portion comes to be enhanced, that is, the dynamic
range of the image data is compressed to correspond to the output
density range in the print.
[0143] On the contrary, the luminance image data that has been
processed by the expansion LUT becomes image data which is positive
(plus) value in the bright portion and negative value in the dark
portion whereby the above-described luminance image data comes to
be added to the primary image data causing expanding the gradation
of the image data.
[0144] The prescanned data and the fine scanned data in which each
dynamic range has been compressed (expanded) by being subjected to
the dodging processing in the above-described manner are sent to
the data converting subsection 70 and the data converting
subsection 74, respectively. It should be noted that an image
processing subsection such as a sharpness processing subsection or
the like may be provided between the adder 88 and each of the
converting subsections.
[0145] The data converting subsection 70 of the prescan processing
section 56 is a site where the prescanned data processed by the
image processing subsection 68 is converted with a 3D
(three-dimensional)-LUT or the like to image data corresponding to
a representation on the display 20.
[0146] On the other hand, the data converting subsection 74 of the
fine scan processing section 58 is a site where the fine scanned
data processed by the image processing subsection 72 is similarly
converted with a 3D (three-dimensional)-LUT or the like to image
data corresponding to image recording with the printer 16.
[0147] In the processing apparatus 14, the image data processed by
the data converting subsection 70 of the prescan processing section
56 and the image data processed by the data converting subsection
74 of the fine scan processing section 58 are sent to the display
20 and the printer 16, respectively.
[0148] It should be noted that the display 20 is not particularly
limited but various types of known display devices such as a CRT
(Cathode Ray Tube), a liquid crystal display and the like can be
used.
[0149] The printer 16 exposes the light-sensitive material
(photographic paper) in accordance with the image data outputted
from the fine scan processing section 58 to record a latent image
which is subsequently subjected to development processing
corresponding to the light-sensitive material to output a
(finished) print.
[0150] To give one example of the printer's operation, the
light-sensitive material is cut to a predetermined length in
accordance with the size of the final print; thereafter, the
printer records a back print and three light beams for exposure to
red (R), green (G) and blue (B) in accordance with the spectral
sensitivity characteristics of the light-sensitive material
(photographic paper) are modulated in accordance with the image
data (recorded image); the three modulated light beams are
deflected in the main scanning direction while, at the same time,
the light-sensitive material is transported in the auxiliary
scanning direction perpendicular to the main scanning direction so
as to record a latent image; the latent-image-bearing
light-sensitive material is then subjected to wet development
processing comprising color development, bleach-fixing, rinsing and
the like; the thus processed light-sensitive material is dried to
produce a finished print; a plurality of prints thus produced are
sorted and stacked.
[0151] Hereafter, the present invention will be described in detail
by describing an operation of the photoprinter 10.
[0152] At the request of print production of the film F, the
operator loads the scanner 12 with the carrier that corresponds to
the film F, sets the film F in a predetermined position on the
carrier, enters necessary commands such as the size of the print to
be produced and the like and, thereafter, keys in a command for
getting the print production started.
[0153] In response to this command, a stop-down value (aperture
size) of the variable diaphragm 24 in the scanner 12 or a storage
time of the image sensor 34 is set in accordance with the reading
condition for prescan and, thereafter, the carrier transports the
film F such that the frame to be subjected to the print production
is transported to a reading position. Further, when the film F is
transported, magnetic information recorded on the magnetic
recording medium or the bar code such as the DX code or the like is
read and necessary information such as the type of the original,
the size of the original (loading information of the carrier is
permissible) and the like are sent to a predetermined site such as
the selecting part 62a of the setup subsection 62.
[0154] Next, the prescan of the frame of interest is started and,
as described above, each color filter of the color filter plates 26
is inserted one after another and each projected light is focused
on the image sensor 34 so that the image of the frame of interest
is separated into three primary colors of R, G and B which are
subsequently captured photoelectrically.
[0155] Both prescan and fine scan may be performed frame by frame;
alternatively, all frames may successively be subjected to prescan
and fine scan; if desired, prescan and fine scan may continuously
be performed on frame groups each consisting of a given number of
frames. On the pages that follow, the case of performing prescan
and fine scan frame by frame is described for the sake of
simplicity of explanation and clarification of the operation.
[0156] The output signals produced from the image sensor 34 by
prescan are amplified by the Amp 36 and sent to the A/D converter
38 where they are converted to digital signals.
[0157] The digital signals are sent to the processing apparatus 14
where they are subjected to specified data processing in the data
processing section 46 thereof, converted to prescanned data in a
digital image data form in the log converter 48 and the resultant
prescanned data is stored in the prescan memory 50.
[0158] When the prescanned data is stored in the prescan memory 50,
the setup subsection 62 of the condition setting section 54 reads
the thus stored prescanned data, constructs the image density
histogram, calculates image characteristic quantities such as
highlights, shadows and the like, sets the reading condition for
fine scanning the frame of interest and then supplies the thus set
reading condition to the scanner 12.
[0159] The setup subsection 62, further, sets image processing
conditions in the prescan processing section 56 and the fine scan
processing section 58 relative to the image (frame) of interest
such as the LUT in the first LUT 76, the compression LUT (expansion
LUT which is hereinafter omitted from description) in the second
LUT or the like in accordance with the image density histogram and
the calculated image characteristic quantities, sometimes in
combination with optionally entered operator's commands and
supplies the thus set image processing conditions to the parameter
coordinating subsection 66. Upon receiving the image processing
conditions, the parameter coordinating subsection 66 sets them at a
predetermined site each in the prescan processing section 56 and
the fine scan processing section 58.
[0160] As described above, the compression LUT in the second LUT is
produced such that the selecting part 62a selects the basic
compression LUT from a plurality of stored basic compression LUTs
(basic expansion LUTs which are hereinafter omitted from
description) in accordance with one or more parameters such as the
type of the original, the size of the original, the image analysis
result and the operator's command and the like and then the setup
subsection 62 produces such compression LUT using the thus selected
basic compression LUT in accordance with the image analysis.
[0161] When the image processing condition is set, the display 20
turns to verification screen. On this occasion, prescanned data is
read from the prescan memory 50 by the prescan processing section
56 and processed with the image processing condition corresponding
to the image data in the image processing subsection 68 to produce
the image (prescan image) which reproduces the prescanned data
which is subsequently represented on the display 20 as a simulation
image (anticipated finish-image).
[0162] Next, looking at the simulation image represented on the
display 20, the operator verifies the image and, if necessary,
manipulates the aforementioned keys on the keyboard 18a or the like
to adjust the color, density, gradation and other features of the
image.
[0163] Inputs for these adjustments are sent to the key correcting
subsection 64 which, in response to the entered inputs for
adjustments, calculates amounts of correction of the image
processing conditions and sends them to the parameter coordinating
subsection 66.
[0164] In response to the supplied amounts of correction, the
parameter coordinating subsection 66 corrects the image processing
condition set in the prescan processing section 56 and the fine
scan processing section 58 or calculates a correction condition for
performing any of the above-described adjustments so that it is set
in a predetermined position in each of the processing sections.
Accordingly, the image represented on the display 20 also varies in
response to this corrective measure, or the inputs for adjustment
entered by the operator.
[0165] If the operator concludes that the image is appropriate
(verification OK), the operator gives a command for print start.
The image processing conditions are finalized in accordance with
this command whereby fine scan gets started. When no image
verification is performed, the image processing conditions are
finalized at the point of time when the parameter coordinating
subsection 66 ends setting of the image processing conditions
whereby fine scan gets started.
[0166] Fine scan is performed in the essentially same manner as
prescan except for the storage time of the image sensor 34 or the
stop-down value of the variable diaphragm 24 so that the output
signals from the image sensor 34 are amplified by the Amp 36,
converted to digital form by the A/D converter 38, processed by the
data processing section 46 in the processing apparatus 14,
converted to fine scanned data by the log converter 48 and sent to
the fine scan memory 52.
[0167] Subsequently, the fine scanned data is read from the fine
scan memory 52 by the fine scan processing section 58, processed by
the image processing condition finalized in the image processing
subsection 72, converted to output image data corresponding to the
image recording by the printer 16 by the image data converting
subsection 74 and sent to the printer 16 where the print is
produced.
[0168] While the image processing method and apparatus according to
the present invention has been described above in detail with
reference to various embodiments, it should be noted that the
invention is by no means limited to the foregoing embodiments and
various improvements and modifications may of course be made
without departing from the scope and spirit of the invention.
[0169] As described above in detail, according to the present
invention, the dodging processing having excellent characteristics
which is capable of substantially decreasing the washed-out
highlight in the bright portion or the flat (dull) shadow in the
dark portion in the scene where the subject is taken with backlight
or the electronic flash can be performed in a shorter period of
processing time than that in a conventional way whereupon
productivity in print production, for example, by the digital
photoprinter or the like can advantageously be enhanced.
* * * * *